Broaching attachment for rock drills



Patented July 6, 1926.

UNITED STATES.

PATENT OFFICE.

cnmns c. nausmw, or EASTON, PENNSYLVANIA, ASSIGNOR ro mennsoLn-nmm comm,or mnsnx our, NEW JERSEY, A conronnrrou or NEW'J'ERSEY.

rnoacnme arr'acnumrr ron nocx mamas.

Application fled November 11, 1925. Serial K036836313.

I This invention relates to rock drills, but

more particularly. to a breaching attachment for fluid actuated rockdrills of the hammer type.

In quarrying slate, granite orsimilar rock formation, it is a commonpractice to remove the rock in the form of rectangular blocks. Aconvenient and practical method of sev-v ering such blocks from 'themass is to drill l a line of holes, leaving a narrow wall of materialbetween adjacent holes. The walls thus formed are then cut away bymeansof a broach. This method of quarrying sym-- metrical blocksof rockhas been found to be considerably more economical than it would be toform a cut with an ordinary drill steel. However, with the front headsheretofore used forbroaching operations it has been exceedinglydifficult to prevent the broach from creeping away from the narrowersection of'the wall between the holes to, the wider part. This obviouslyrequires the removal of a greater amount of material and consequentlyincreases the operating 'costs. 1

It is accordingly tion to enable a broaching tool to be rigidly guidedand held against any tendency to depart from a desired course.

Another object is to construct abroaching attachment which may bequickly substituted for an ordinary rock drill front head and which willpermit quick removal of the broaching tool from the attachment.

Further objects will be in part obvious .and in part pointed outhereinafter.

The invention consists of the combinations of elements, features ofconstruction and arrangement *ofparts having the general mode ofoperation substantially as hereinafter descnbed and more particularlypointed out in the appended claims and illustrated in the accompanyingdrawin s, in which Figure 1 is an elevation o the front end of a rockdrill equipped. with an attachment constructed inaccordance with the'invention with the guiding block removed inillustrating one of, itsuses,

Figure 2 is an elevatlon partly in section taken through Figure 1 on theline 22 looking in the direction of the arrows,

' Figure 3 is a perspective view illustrating the manner in which theguide block may be removed from the attachment for the purpose ofremoving the breaching tool, and

an object of this inven- Figure 4 is .a transverse sectional view takenthrough Figure 2 on the line 4-4: looking in the direction of thearrows.

Referring to the drawings, the invention is shown embodied in a rockdrill of which only a front portion of a cylinder A is shown. Within thecylinder A is a bushing B which acts as a guidefor a hammer piston Cadapted to reciprocate therein to deliver blows to an anvil block D.

In accordance with the present invention, an attachment or a front headE is su ported by the cylinder A and preferab y secured thereto by meansof a pair of cushioned side bolts. F which extend through lugs G and Hof thecylinder A and the front head' E respectively. The bolts F areprovided with springs J which serve to hold the front head E yieldablywithin the cylinder A, Nuts K screwed on the ends of the bolts F providea seat for one end of the springs J and also serve as a means foradjusting the tension of said springs.

The front head E in this instance has a forwardly projectin cylindricalportion L to which is preferably secured integrally an extension 0provided on its inner face P with a fiat cheek plate Q having a planesurface which in this instance serves as a guide 'for one face of abroaching tool R. 'f The check plate, Q'is preferably somewhat short-'er than the face P so that a shoulder S is ably equal to the combined,thickness of the tool R and the cheek plate Q so that the sides of therecess will. also closely engage the sides of the cheek plate Q and thusserve to prevent lateral movement of the guide block V with respect tothe extension 0. At the inner end of the recess W is formed a shoulder Ysimilar to the shoulder S on the extension 0 and adapted to be in linetherewith when the guide block V is secured in position on the extensionIn this way the head U of the breaching tool B may impact equallyagainst bothshoul.- ders. A space Z formed by the shoulders S v 9breaching tool R which extends into the and Y provides a path for thehead U of the breaching "tool so that it may extend freely into the pathof the anvil block D to receive the blows transmitted by said anvil.block from the piston C.

Convenient means are provided for quick-. ly securing the guide block Vto the exten-' sion 0. To this end the extension 0 is pro vided withslots 6 at its sides to receive eyebolts 0 which in this instance arepivoted on, c

0, one end of the gul mg surface, remova pins d arranged through theextension Suitable slots 6 are likewise formed in the guide block V toreceive the eye-bolts 0. Nuts 7 are in this instance screwed on theendsof the eye-bolts o for the purpose of clamping the guide block Vfirmly in posi-' tion.

The cutting face 9 of the breaching tool iRis preferably concave and isof suflicient length to extend well on opposite sides of a wall Itformed. by the drill holes in the rock 70. The cutting face 9 of thebroaching tool R is preferably of only slightly greater, thickness thanthe narrowest portion of the wall 71 so that only a minimum ambunt ofmaterial will have to be'rcmoved' between the holes j,

The advantages of this invention reside chiefly in the fact that thatend of the front head may be of equal cross sectional area'as thatportion of the tool exterior of the front head. In this way a highdegree of rigidity may be obtained in the breaching tool and thetendency of the breaching tool to creep or depart from the desired lineis eliminated.

I claim:

1. In a broaching. attachment for fluid actuated rock drills ofthe'hammer type having a cylinder and a reciprocatory hammer piston inthe cylinder, the combination of a front head adapted to be secured. tothe cyhnder and having an extension, a cheek plate on the extensionforming a plane guiding surface, and means engaging the mer piston inthe 'tion of a front head adapted to be secured ing a plane cheek plateto cooperate with said plane surface of the extension for guiding abreaching tool.

2. In a broaching attachment for fluid actuated rock drillsof the hammertype having a cylinder and ai reciprocato-ry hammer piston in thecylinder, the combination. of a front head adapted to be secured to thecylinder and having an extension formed with a plane guidin surface, ashoulderbait e means cooperating with the guiding surface of saidextension to form a guide broaching tool, and a shoulder on the saidmeans to lie in the same transverse plane as for a tain-ing suchbroaching tool in the attachment. r

3. In a breaching attachment for fluid actuated rock drills of thehammer type having a cylinder and a reciprocatory hamcylinder,- thecombinato the cylinder and having an extension provided with a planesurface, a recessed guide block removably securedto the extension andcooperating with said plane surface of the extension for guidingabroaching tool, and means for clamping said guide block to theextension.

4. In a breaching attachment for fluid actuated rock drills of thehammer type having acylinder and a reciprocatory hammer piston in thecylinder, the combination of a front head adapted to be secured to thecylinder, an extension on the front head, havcheek plate forming oneside of a guideway, a removable guide block having a recess to receiveand guide a broaching tool. said recess cooperating with the cheek platefor preventing lateral movement of the guide block, and means forclamping the guide block in position.

In testimony whereof I have signed this H specification.

' CHARLES C. HANSEN.

